Endocrinology, Vol 107, 183-186, Copyright © 1980 by Endocrine Society
Effect of estrogen on thyrotropin-releasing hormone-induced release of prolactin in intact, ovariectomized, and stalk-sectioned female rhesus monkeys
WP Diefenbach, A Dennison, H Rosenblatt, L Vaughan, AG Frantz and M Ferin
The effects of estrogen treatment on basal and TRH-induced serum PRL
concentrations were studied in three groups of four female rhesus monkeys;
intact monkeys, ovariectomized animals, and monkeys in which the pituitary
gland had been isolated from direct hypothalamic influences by pituitary
stalk section. The TRH tests (50 microgram, iv) were performed before and 7
and 21 days after the sc implantation of one or two 3-cm long silastic
capsules containing 17 beta-estradiol. Treatment with estradiol
significantly increased the PRL response to TRH in the three groups of
animals. The highest PRL response to TRH was observed after stalk section.
The estrogen treatment also increased basal PRL concentrations in
stalk-sectioned monkeys but no statistically significant increase was
observed in intact or ovariectomized animals. These results indicate that
physiological amounts of estradiol increase the magnitude of TRH-induced
PRL release in rhesus monkeys, and that this estrogen effect is probably
enacted directly at the level of the anterior pituitary gland.
